Sol-Gel Synthesis and Electrochemical Performance of LiMnPO4/C Cathode Material

Abstract

LiMnPO4/C composite as a cathode material for lithium ion batteries was synthesized via a Sol-Gel method using tributyl phosphate as both chelating agent and phosphor source while lauric acid as a carbon source. Crystalline structure and morphology of the composite were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM). The results indicate that the LiMnPO4/C composite is well crystallized as an olivine structure without any detectable impurity phase at annealing temperature of 700℃. The spherical-like LiMnPO4/C microparticles are composed of large numbers of nanoparticles with the size ranging from 50 nm to 100 nm, which are covered with a thin carbon layer. Cyclic voltammetry and gal- vanostatic charge-discharge tests reveal that LiMnPO4/C composite has superior electrochemical performance. The initial discharge capacities of LiMnPO4/C are 141 and 113 mAh/g at rates of 0.05C and 0.5C under room tempera- ture, respectively, along with high cyclic stability and good charge-discharge performances under high and low